The present invention relates to a ball transfer deck that facilitates movement of heavy loads and an associated pin stop mechanism installed in the ball transfer deck that can be selectively engaged to prevent the movement of a particular load across the load-bearing support surface of the deck.
Ball transfer decks are commonly used in air cargo and other material handling industries to move heavy loads such as cargo containers. Typically, a ball transfer deck comprises a series of ball transfer units (BTUs) installed in openings in a generally horizontal support surface. Each BTU has a ball or roller contained in a housing with the ball being freely rotatable with respect to the housing. Each BTU is installed such that the roller projects above the support surface. The ball contacts a portion of the bottom surfaces of the loads being conveyed along the deck. Proper placement of the BTUs along the deck ensures that the loads do not contact the support surface of the deck itself but contact only the balls of the BTUs. Loads are thus easily moved either manually or mechanically over the BTUs.
A variety of BTUs have been developed in the prior art in an effort to improve the performance of the BTUs and/or to extend the life of the BTUs. See, for example, U.S. Pat. Nos. 5,540,314 and 5,464,086 issued to Coslin. Still, the basic structure of most BTUs is essentially the same, generally comprising a cylindrical sleeve with an upper flange that houses a ball roller. The sleeve is inserted through an opening in the surface of the deck with the upper flange of the BTU abutting the upper surface of the deck, thereby preventing the BTU from being pushed through the deck under the weight of the conveyed loads. This simple construction also allows for the rapid removal and replacement of damaged BTUs.
Despite improvements in BTU design and construction, a problem that still persists in relation to typical ball transfer decks is the intense noise that often results from the rapid movement and conveyance of loads over the surface of the BTUs. Thus, it is a paramount object of the present invention to provide for a simple construction of BTUs that will reduce attendant operating noise while not increasing manufacturing costs or adding undue complexity to the design of the BTU.
The present invention also seeks to address typical problems associated with stopping the movement of loads across prior art ball transfer decks. When conveying cargo containers or other loads across a ball transfer deck, it is often necessary to stop movement of a particular load or to maintain a particular load in a stationary position despite movements of other loads. To accomplish this, pin stop mechanisms are often incorporated into the ball transfer deck. A pin stop mechanism is generally comprised of a steel post or pin that is spring loaded into a sleeve. The mechanisms are preferably constructed so that they will slide into the same openings in which the BTUs are positioned. In a first position, the pin of the pin stop mechanism is in a recessed position, i.e., housed within the sleeve below the level of the conveying surface defined by the rollers of the BTUs. When it is necessary to stop movement of a load across the deck, the pin is extended into a second position in which the distal end of the pin projects above the level of the BTUs, thereby preventing movement of a load over the deck.
Such prior art pin stops, however, have attendant disadvantages. For example, typical prior art pin stop mechanisms are frequently damaged by the repeated impacts of conveyed loads against the extended pins. In some instances, these impacts may cause a pin to lean laterally, thereby damaging the edge of the associated opening in the ball transfer deck. Not only might this cause the pin stop mechanism to fall through the ball transfer deck when the load is released, but such damage to the openings in the ball transfer deck also makes it difficult to replace the damaged pin stop mechanism. Thus, it is another important object of this present invention to provide for a ball transfer deck in which the pin stop mechanisms better withstand the repeated impacts of heavy loads against the pins, thereby preventing damage to the pin stop mechanisms and associated openings in the deck surface.
These and other objects and advantages of the present invention will become apparent upon a reading of the following description and appended claims.